1. Technical Field
The invention relates to seismic prospecting and geological exploration, and more particularly to a drilling rig having a vibrator systems affixed thereto that is used for forming holes in the earth using a pipe string.
2. Background Art
Land based seismic prospecting and geological exploration are well established arts. Generally, a movable drilling or exploration rig is assembled at a selected location where a hole is to be formed in the earth's crust. Typically, one or more sections of pipe, which form a drill string, with a drilling bit is used to rotary drill a hole in the ground or, alternatively, may be pushed into the earth either by a constant force in the desired direction or by a vibratory force applied on the upper exposed portion of the drill string.
Combining a vibratory system with other known types of apparatus for pile driving or earth boring, including such methods as rotary drilling or hammering, can improve the efficiency of the earth boring. The following U.S. patents relate generally to the use of vibratory systems in earth boring or pile driving:
U.S. Pat. No. 5,281,775; PA0 U.S. Pat. No. 4,553,443; PA0 U.S. Pat. No. 3,920,083; PA0 U.S. Pat. No. 3,753,242; PA0 U.S. Pat. No. 3,394,766; and, PA0 U.S. Pat. No. 3,106,258.
U.S. Pat. No. 5,281,775 issued to Gremillion teaches a vibrating hole forming device for seismic exploration. A vertically mounted pipe is disclosed as having an attached rack gear cooperating with a hydraulically operated pinion to push the drill string into the ground forming the hole. At a predetermined pressure against further downward movement of the drill string, a vibrator is engaged. The vibratory motion is transmitted to the drill string at a point between the ends of the uppermost section of pipe, and thus not necessarily in a direction parallel to the longitudinal axis of the drill string.
U.S. Pat. No. 4,553,443, issued to Rossfelder, also discloses a vibrator system for earth boring. Similar to that as taught by Gremillion, the vibrator is attached to the pipe at a mid-position between the end placed in the ground and the upper end of the pipe.
U.S. Pat. No. 3,106,258 shows a vibratory pile driving device having the vibrator mechanism clamped to the top of the pile shaft being driven into the ground. The vibrations caused by the exciter are isolated from the supporting rig structure by means of compression springs.
It is therefore a feature of this invention to provide an improved hole forming device for earth boring.
It is a further feature of this invention a simplified drilling rig including a mechanical vibrator system to assist the pipe string in penetrating extremely dense subsurface features.
It is still a further feature of this invention that it can employ a hammer-type approach with varying frequencies to drilling includable with the known types of rotary drilling rigs.